Felony assault charges have been filed against the seventh grade student accused of Tuesday's middle school shooting in Roswell, N.M.

Mason Campbell, 12, has been charged with three counts of aggravated assault with a deadly weapon, according to documents filed Wednesday at the Chaves County Fifth Judicial District Court. The charges are third-degree felonies. He is accused of using a shotgun to fire three times in the gym before classes started on Tuesday morning at Berrendo Middle School, striking a 11-year-old boy and 13-year-old girl.

Today Campbell's family released a statement saying they are "heartbroken" over the incident.

"We are horribly sad over this tragedy on so many levels," Jim and Jennifer Campbell, the boy's parents, and Robert and Nancy Bowles, his grandparents, said in the statement. "We are praying that God will be with everyone who has been affected. For all of the anguish that many suffered yesterday, our family offers our heartfelt condolences and remorse in words that we cannot fully express."

The family said it "will cooperate in all ways with law enforcement."

Police said today that the accused student may have planned out the attack, sawing off the stock of the shotgun and possibly warning some classmates as he entered the school.

According to police, one shell hit the ceiling, one hit the floor, and the other was fired into the bleachers area where the two students were seated.

New Mexico State Police Chief Pete Kassetas said today that police executed search warrants overnight, searching the boy's school locker, home, and the duffel bag he used to bring the gun to school.

The gun belonged to his parents, but the student sawed off the handle of the gun to make it more like a "pistol grip" weapon, and loaded it with three shells.

Kassetas said there is some indication that the boy verbally warned "select students" about the attack as he arrived at the school.

Kendal Sanders, the 13-year-old girl who was struck, is in stable condition with injuries to her arm. The male student, who was shot in the face and neck, is in critical condition. His identity has not been made public.

Police said the district attorney is still working on charging the boy.

Authorities declined to answer questions about a motive today, but knocked down reports Tuesday night that the suspect targeted the 12-year-old boy.

"When the incident occurred, the victims were random," Kassetas said.

Kassetas reiterated that police were looking at social media accounts and other forms of communications as part of their investigation.

The shooting began and ended within 10 seconds, according to police. After he heard two shots fired, eighth grade teacher John Masterson convinced the suspect to put the gun down and his hands up, police said. The boy was then apprehended.

Kassetas said that an off-duty state police trooper, Lt. Gary Smith, was dropping his child off at the school when the shooting occurred and helped apprehend the boy.